Experiments will be conducted to determine the chronic effects of small concentrations of ozone on the metabolism of rats and mice in the presence of normal and high levels of polyunsaturated fatty acids in the diet, and in the presence and absence of vitamin E an DPPD a synthetic antioxidant. Animals will be exposed continuously throughout their life span to one of the following gases: 0.1 ppm and 0.3 ppm of ozone, and ambient air. The following parameters of response will be determined: (a) gross and histopathology of tissues and organs, (b) growth rate, (c) reproductive performance, (d) longevity, (e) concentration of lipofuscin pigments in the tissues, (f) rate of oxidation of vitamin E in vivo, (g) malondialdehyde (a carcinogen) concentration of tissues, (h) changes in fatty acid distribution in tissues, (i) glutathione peroxidase activity, and (j) superoxide dismutase activity. The effect on the susceptibility of the animals to ozone, of depriving them of the natural lipid antioxidant vitamin E, of providing them with high levels of this vitamin, and of administering the synthetic antioxidant DPPD, also will be determined. In separate experiments the effect of ozone on vitamin E metabolism and linoleic acid oxidation in vivo will be studied by the use of rats as experimental animals and C14 alpha-tocopherol and C14-linoleic acid as radioisotopes.